I. Field of the Invention
This invention is in the field of preparing higher order cuprate complexes from vinyl stannane compounds as reactive intermediates in organic synthesis. Higher order cuprate complexes derived from the reaction of a cuprate complex with 1,2-bis-tri-n-butylstannyl ethylene are particularly useful for the addition to epoxides to form vinyl tin intermediates that are useful for preparing omega side chains of prostaglandins, particularly 16-hydroxy prostaglandin side chains.
II. Prior Art
The state of the art of higher order cuprate complexes is summarized in Syntheis, #4, p. 325, (1987) where higher order cuprate complexes of the formulae R.sub.t RCu(CN)Li.sub.2, R.sub.t Cu(2-thienyl)CNLi.sub.2, and R.sub.t RCu(SCN)Li.sub.2 and their use are disclosed. R.sub.t represents the group transferred to an organic compound to form a carbon to carbon bond in a subsequent reaction with the complex.
U.S. Pat. No. 4,499,296 describes the preparation of a large number of prostaglandins prepared by the sequence of reactions set out in the following steps:
(i) a stannane compound of the formula ##STR1## is reacted with alkyl lithium in one reaction vessel; (ii) an organo copper compound is formed in a separate vessel; PA0 (iii) the reagents formed in (i) and (ii) are mixed together and added to a cyclopentenone: ##STR2## to provide prostaglandins of formula I ##STR3## wherein, R'" is --CO.sub.2 R""; PA0 R"" is hydrogen or lower alkyl containing 1 to 6 carbon atoms; PA0 R' is lower alkyl containing 1 to 6 carbon atoms, vinyl or ethynyl; PA0 R" is alkyl or cycloalkyl containing 3 to 5 carbon atoms; and PA0 the wave line represents R,S stereochemistry. PA0 (b) each R is independently lower alkyl, alkenyl, phenyl, naphthyl, phenanthryl, or thienyl, provided that (i) each of the aforementioned radicals may be substituted with non-interfering substituents and (ii) only one R in the first cuprate complex may be alkenyl, phenyl, naphthyl, phenanthryl, or thienyl; and PA0 (c) each R.sup.1 is independently lower alkyl;
JACS 94 7210 (1972) describes lithium copper vinyl complexes. Prostaglandin Synthesis, Academic Press, 1977, Chapt. 7 describes prostaglandin synthesis generally. U.S. Pat. Nos. 4,449,296; 4,322,543; 4,578,505; and 4,271,314 describe organotin intermediates in the preparation of prostaglandins.